GLSL ROTATION ABOUT AN ARBITRARY AXIS

mat4 rotationMatrix(vec3 axis, float angle){
axis = normalize(axis);
float s = sin(angle);
float c = cos(angle);
float oc = 1.0 - c;

return mat4(oc * axis.x * axis.x + c, oc * axis.x * axis.y - axis.z * s, oc * axis.z * axis.x + axis.y * s, 0.0,
oc * axis.x * axis.y + axis.z * s, oc * axis.y * axis.y + c, oc * axis.y * axis.z - axis.x * s, 0.0,
oc * axis.z * axis.x - axis.y * s, oc * axis.y * axis.z + axis.x * s, oc * axis.z * axis.z + c, 0.0,
0.0, 0.0, 0.0, 1.0);

}

mat4 rotationMatrix(vec3 axis, float angle) {vec3 a = normalize(axis);float s = sin(angle);float c = cos(angle);float oc = 1.0 – c;float sx = s * a.x;float sy = s * a.y;float sz = s * a.z;float ocx = oc * a.x;float ocy = oc * a.y;float ocz = oc * a.z;float ocxx = ocx * a.x;float ocxy = ocx * a.y;float ocxz = ocx * a.z;float ocyy = ocy * a.y;float ocyz = ocy * a.z;float oczz = ocz * a.z;return mat4(vec4(ocxx + c, ocxy – sz, ocxz + sy, 0.0),vec4(ocxy + sz, ocyy + c, ocyz – sx, 0.0),vec4(ocxz – sy, ocyz + sx, oczz + c, 0.0),vec4( 0.0, 0.0, 0.0, 1.0));}